Operation lock for fire hydrants

ABSTRACT

A device for discouraging the unauthorized opening of a fire hydrant consisting of a key member carried movably by the top stem of the fire hydrant and having an operative position in which it interlocks said stem with a non-rotatable portion of the hydrant to prevent rotation of the stem to open the main valve of the hydrant, and an inoperative position in which it permits rotation of the top stem, a spring biasing the key member to its operative position, release of the key member utilizing a specially modified wrench to be applied to the wrench lug of the top stem.

United States Patent [191 Polkey Sept. 2, 1975 OPERATION LOCK FOR FIREHYDRANTS [75] Inventor: Stephen T. Polkey, Kansas City, Mo. [73]Assignee: Louis Macher, Kansas City, Mo.

[22] Filed: Nov. 26, 1973 [21] Appl. No.: 419,064

[56] References Cited UNITED STATES PATENTS 5/1905 Chenery ..251/291 X7/1907 Henson 5/1915 10/l933 8/1943 Fuehrer 251/110 X 12/1972 Greenwood81/121 R [5 7] ABSTRACT A device for discouraging the unauthorizedopening of a fire hydrant consisting of a key member carried movably bythe top stem of the fire hydrant and having an operative position inwhich it interlocks said stem with a non-rotatable portion of thehydrant to prevent rotation of the stem to open the main valve of thehydrant, and an inoperative position in which it permits rotation of thetop stem, a spring biasing the key member to its operative position,release of the key member utilizing a specially modified wrench to beapplied to the wrench lug; of the top stem.

6 Claims, 9 Drawing Figures OPERATION LOCK FOR FIRE HYDRANTS Thisinvention relates to new and useful improvements in fire hydrants, andhas particular reference to the provision of means for discouraging theunauthorized opening of fire hydrants. Such unauthorized openings.particularly by children during hot weather, are of course quite common,and annually represent a loss of many millions of dollars. At the sametime, the emergency nature of the intended and normal usage of firehydrants requires that they be instantly available for usage and easilyopened by authorized personnel.

Accordingly, the principal object of the present invention is theprovision of a very simple device for locking the top stem of thehydrant against rotation, such rotation being required to open the mainvalve of the hydrant, whereby to discourage opening thereof byunauthorized persons. Nevertheless, application of a special wrench tothe wrench lug of the stem, such wrench being in the possession ofauthorized personnel only, and differing from the usual lug wrench in away not obvious to the casual observer, will instantly release thelocking device to permit normal rotation of the stem. Generally, thisobject is accomplished by the pro vision of a sliding key memberinserted in the top stem and normally spring-biased to a positioninterlocking with a non-rotatable element of the hydrant structure,whereby to lock the stem against rotation, but being movable to aninoperative position by a pin fixed in an otherwise standard lug wrench,whenever said wrench is applied to the stem lug.

Another object is the provision of an operation lock for fire hydrantsof the character described which can be applied very simply andeconomically to most preexisting fire hydrants, requiring only thereplacement of the usual top stem and hold-down nut with similar butspecially formed elements. The top stem and holddown nut arestructurally minor elements of the total hydrant structure, and areeasily removable.

Otherobjects are simplicity and economy of construction. and efficiencyand dependability of operation.

With these objects in view, as well as other objects which will appearin the course of the specification, reference will be had to theaccompanying drawing, wherein:

FIG. I is a fragmentary vertical sectional view of a fire hydrant,showing the top portion thereof, and including an operation lockembodying the present invention,

FIG. 2 is an enlarged fragmentary sectional view taken on line II-II ofFIG. 1, showing the top stem locked against rotation,

FIG. 3 is a view similar to FIG. 2, showing the top stem unlocked forrotation by the application of a special wrench thereto,

FIG. is a top plan view of the top stem and related elements shown inFIG. 2,

FIG. 5 is a fragmentary sectional view taken on line V-\ of FIG. 2,

FIG 6 is a fragmentary sectional view taken on line VI--\ l of FIG. 3,

FIG. 7 is an enlarged side elevational view of the key member of thedevice,

FIG. 8 is a left side view of the key member as shown in FIG. '7, and

FIG. 9 is a top plan view of the key member.

Like reference numerals apply to similar parts throughout the severalviews, and the numeral 2 applies to the barrel of a fire hydrant, saidbarrel having the form generally ofa vertical pipe extending both aboveand below ground level. Below ground level, it is connected to anunderground water supply pipe through a main valve operable by a mainstem 4 which extends upwardly through barrel 2, the valve being openedby raising said stem, and closed by lowering said stem. The stem itselfis non-rotatable. This underground structure may be standard and wellknown in the art, and is not here shown. Above ground level, barrel 2 isclosed at its upper end by a dome member 6 affixed thereto, and isprovided with side outlets 8 to which water is sup plied when the mainvalve is open, said outlets being provided with removable caps 10.

Dome 6 is provided with a central vertical aperture 12, the upperportion of which is of enlarged diameter to form a socket 14 openingthrough the top of the dome. The upper portion of said socket isinternally threaded. A generally cylindrical top stem 16 is inserteddownwardly through aperture 12 into the interior of dome 6, having aninternally threaded socket 18 in its lower end portion into which theupper end of main stem 4 is threaded, and also extends above the dome.Said top stem is provided with an external flange 20 which rotatablyengages the base of socket 14, an anti-friction washer 22 beinginterposed therebetween. An oil-impregnated packing 24 is also insertedin the socket around the peripheral edge of flange 20. The flange issecured in socket 14, whereby to permit rotation thereof but preventupward movement thereof, by a tubular hold-down nut 26 through which topstem 16 extends for rotation, and which is threaded into the top portionof socket 14. The hold-down nut is provided with a wrench lug 28 bymeans of which it may be tightly set, and the portion of the top stemprojecting above said nut is formed with a polygonal contour to presenta wrench lug 30.

The structure thus far described is common and well known in the art, itbeing apparent that rotation of top stem 16 by a wrench of the propercontour applied to its lug 30 will cause raising or lowering of mainstem 4 to open or close the main valve, since said main stem is notitself rotatable, However, it is also readily subject to operation byunauthorized personnel. Lug 30 is commonly made pentagonal in form, asshown in FIG. 4, on the theory that since wrenches adapted for this oddshaped lug are not commonly available, it would tend to preventunauthorized openings. However, this mea sure has been at best onlypartially effective for this purpose, since the top stem may still beturned readily by use of an ordinary pipe wrench.

In accordance with the present invention, a much more effectivedeterrent to unauthorized opening is obtained by modification of topstem 16 and hold-down nut 26, so as to require a special wrench 32 forturning lug 30. Top stem 16 is modified by forming an annularlysegmental socket 34 in the top surface of flange 20 thereof, the innerradius of said socket being equal to the top stem radius above saidflange, drilling a circular socket 36 axially into the upper end of lug30, and cutting a radial slot 38 in said stem, said slot extendingthrough the top of lug 30 and communicating with socket 36, andextending downwardly to the base of flange socket 34 to communicate withsaid socket. Movable in sockets 34 and 36, and slot 38, is a key memberdesignated generally by the numeral 40 and best shown in FIGS. 7-9. Saidkey member comprises a cylindrical plug 42 carried slidably in socket36, a planar blade member 44 fixed at its upper end to said plug andcarried for vertical sliding movement in slot 38, and an annularlysegmental locking bar 46 with its plane of curvature disposed in a planenormal to the stem axis and affixed at its midpoint to the lower end ofblade 44. Said locking bar is curved correspondingly to and is engagedfor vertical movement in socket 34 of the stem flange. Said bar is ofsuch vertical thickness that when the key member is depressed as shownin FIG. 3, it is contained wholly within socket 34, but the key memberis biased upwardly by a compression spring 48 carried in the baseportion of socket 36 beneath plug 42, whereby locking bar 46 tends torise above flange 20. Hold-down nut 26 is modified by the formation, inthe bottom surface thereof, of one or more annularly segmental sockets50, two such sockets being shown in diametrically opposite relation.Each of sockets 50 is disposed to receive locking bar 46 therein whenthe latter is urged upwardly by spring 48, provided that top stem 16 hasbeen turned to align its flange socket 34 with one of nut sockets 50.

In operation, it will be seen that FIG. 2 shows the parts in the normallocked position of the device. Key member 40 is held in its elevatedposition by spring 48. In this position, locking bar 46 is engaged inone of sockets 50 of the hold-down nut, but since sockets 50 are not ofsufficient depth to receive the entire vertical thickness of the lockingbar therein, said locking bar remains partially engaged in socket 34 ofthe stem flange, as shown. The stem is thus locked against rota tionrelative to the hold-down nut 26, and the stem therefore cannot beturned to open or close the hydrant valve by any ordinary wrench appliedto stem lug 30. To prevent the hold-down nut itself from being turned bytorque applied to lug 30, said nut is for the purposes of this inventionseated so firmly, or cemented or otherwise secured in place so tightlythat it cannot be loosened and turned by any manually operable means. Inthis position of the key, the upper ends of plug 42 and blade 44 areflush with the upper end of lug 30, and the outer edge of blade 44 isconfigurated to conform precisely to the contour of the lug and stem.Thus, if the parts are well made, even the mere presence of the plug andblade will be scarcely noticeable, and in many cases may escapedetection. In any case, the purpose and function of the key member willnot be selfevident, and will defy and discourage many, particularlycurious children.

However, whenever key member 40 is pressed downwardly against spring 48,locking bar 46 fully enters socket 34 of the stem flange and is fullycontained thereby. The stem may then be turned freely to open or closethe hydrant valve. Key 40 may be depressed in any suitable manner,perhaps most conveniently by a special wrench 32 as shown in FIG. 3,which normally would be in the possession of authorized personnel only.This wrench may be standard in most respects, having a socket member 54having formed therein a polygonal socket 54 adapted to be engagednonrotatively over stem lug 30, and having a radially extending handle58 of any desired length. It is modified by the addition thereto of astud 60 affixcd in socket member 54 and projecting axially into socket56. Whenever the wrench is applied normally to stud 30 as shown in FIG.3, stud 60 engages the top end of plug 42 and depresses key member 40 tounlock the device, as described. Neither the presence nor the functionof the stud will be apparent to a casual observer.

While I have shown and described a specific embodiment of my invention,it will be readily apparent that many minor changes of structure andoperation could be made without departing from the spirit of theinvention.

What I claim as new and desire to protect by Letters Patent is:

1. In a fire hydrant including a fixed, rigid portion and a stem memberoperable by rotation thereof to open and close the valve of saidhydrant, said stem member and said fixed hydrant portion being providedwith mating surfaces normal to the rotational axis of said stem member,said mating surfaces having corresponding sockets formed therein inradially offset relation from said axis and opening toward each other,whereby to register with each other at one angular position of said stemmember, a locking device comprising a key member carried movably by saidstem member, said key member including a locking bar carried by saidstem member for movement in a direction parallel to the stem axis anddisposed in one or both of said sockets, said locking bar being adaptedby said movement to be disposed entirely within one of said sockets,this being its inoperative position, in which said stem is freed forrotation, or partially within both of said sockets, this being itsoperative position, in which it locks said stem against rotation,resilient means biasing said key member to said operative position, andmanually operable means for moving said key member to said inoperativeposition against said biasing means.

2. The structure as recited in claim 1 wherein the depth of one of saidsockets, in a direction parallel to the stem axis, is at least as greatas the thickness of said locking bar in the same direction, whereby tobe capable of containing said locking bar completely, wherein the depthof the other of said notches is less than the thickness of said lockingbar, also in a direction parallel to the stem axis, and wherein saidresilient means biases said locking bar toward engagement with theshallower of said sockets.

3. The structure as recited in claim 2 wherein said stem member projectsoutwardly of said hydrant, and wherein said key member includes a blademember affixed to said locking bar and extending therefrom through saidstem member to the outer end thereof, said blade member being movablerelative to said stem member in a direction parallel to the stern axis,whereby said key member may be operated from the outer end of said stemmember.

4. The structure as recited in claim 3 wherein said resilient meansbiases said key member toward the outer end of said stem member, wherebysaid locking bar may be moved to its inoperative position by inwardpressure on the outer end of said blade member.

5. The structure as recited in claim 4 wherein the outwardly projectingportion of said stem member is configurated to form a wrench lug adaptedto be turned by a socket wrench, whereby said key member may be moved toits inoperative position by inward pressure exerted on the outer end ofsaid blade member by means of a stud fixed in said socket wrench andprojecting into the socket thereof parallel to the axis thereof.

6. The structure as recited in claim 1 wherein said stem member extendsrotatably through an aperture formed therefor in a wall of said hydrant,is configurated at its outer end to form a socket wrench lug, and isprovided intermediate its ends with an external flange carried rotatablyin an external socket of said hydrant wall, said flange being secured insaid hydrant wall socket by a tubular hold-down nut surrounding saidstem member and fixed in said hydrant wall socket, said stem flangehaving an annularly segmental socket formed in the outer surface thereofconcentrically with its axis, and said stem member having an axial boreformed in the outer end thereof and a radial slot formed thereininterconnecting said bore and said socket, and said hold-down nut havingan annularly segmental socket formed in the inner end surface thereofwhich mates with the: outer surface of said stem flange, whereby toregister with said stem flange socket at one angular position of saidstem, and wherein said key member comprises a plug carried slidably inthe outer end bore of said stern member, an annularly segmental lockingbar operable in said stem flange and nut sockets, and a blade memberdisposed entirely in said slot for sliding movement parallel to thestern axis, and rigidly interconnecting said plug and said locking bar,the depth of said stem flange and nut sockets, in a direction parallelto the stem axis, being respectively at least as great as, and lessthan, the thickness of said locking bar in the same direction, saidresilient means biasing said key member toward the outer end of saidstem member.

1. In a fire hydrant including a fixed, rigid portIon and a stem memberoperable by rotation thereof to open and close the valve of saidhydrant, said stem member and said fixed hydrant portion being providedwith mating surfaces normal to the rotational axis of said stem member,said mating surfaces having corresponding sockets formed therein inradially offset relation from said axis and opening toward each other,whereby to register with each other at one angular position of said stemmember, a locking device comprising a key member carried movably by saidstem member, said key member including a locking bar carried by saidstem member for movement in a direction parallel to the stem axis anddisposed in one or both of said sockets, said locking bar being adaptedby said movement to be disposed entirely within one of said sockets,this being its inoperative position, in which said stem is freed forrotation, or partially within both of said sockets, this being itsoperative position, in which it locks said stem against rotation,resilient means biasing said key member to said operative position, andmanually operable means for moving said key member to said inoperativeposition against said biasing means.
 2. The structure as recited inclaim 1 wherein the depth of one of said sockets, in a directionparallel to the stem axis, is at least as great as the thickness of saidlocking bar in the same direction, whereby to be capable of containingsaid locking bar completely, wherein the depth of the other of saidnotches is less than the thickness of said locking bar, also in adirection parallel to the stem axis, and wherein said resilient meansbiases said locking bar toward engagement with the shallower of saidsockets.
 3. The structure as recited in claim 2 wherein said stem memberprojects outwardly of said hydrant, and wherein said key member includesa blade member affixed to said locking bar and extending therefromthrough said stem member to the outer end thereof, said blade memberbeing movable relative to said stem member in a direction parallel tothe stem axis, whereby said key member may be operated from the outerend of said stem member.
 4. The structure as recited in claim 3 whereinsaid resilient means biases said key member toward the outer end of saidstem member, whereby said locking bar may be moved to its inoperativeposition by inward pressure on the outer end of said blade member. 5.The structure as recited in claim 4 wherein the outwardly projectingportion of said stem member is configurated to form a wrench lug adaptedto be turned by a socket wrench, whereby said key member may be moved toits inoperative position by inward pressure exerted on the outer end ofsaid blade member by means of a stud fixed in said socket wrench andprojecting into the socket thereof parallel to the axis thereof.
 6. Thestructure as recited in claim 1 wherein said stem member extendsrotatably through an aperture formed therefor in a wall of said hydrant,is configurated at its outer end to form a socket wrench lug, and isprovided intermediate its ends with an external flange carried rotatablyin an external socket of said hydrant wall, said flange being secured insaid hydrant wall socket by a tubular hold-down nut surrounding saidstem member and fixed in said hydrant wall socket, said stem flangehaving an annularly segmental socket formed in the outer surface thereofconcentrically with its axis, and said stem member having an axial boreformed in the outer end thereof and a radial slot formed thereininterconnecting said bore and said socket, and said hold-down nut havingan annularly segmental socket formed in the inner end surface thereofwhich mates with the outer surface of said stem flange, whereby toregister with said stem flange socket at one angular position of saidstem, and wherein said key member comprises a plug carried slidably inthe outer end bore of said stem member, an annularly segmental lockingbar operable in said stem flange and nut sockets, and a blade memberdisposed entirely iN said slot for sliding movement parallel to the stemaxis, and rigidly interconnecting said plug and said locking bar, thedepth of said stem flange and nut sockets, in a direction parallel tothe stem axis, being respectively at least as great as, and less than,the thickness of said locking bar in the same direction, said resilientmeans biasing said key member toward the outer end of said stem member.